//========================================================================
//Copyright 2007-2011 David Yu dyuproject@gmail.com
//------------------------------------------------------------------------
//Licensed under the Apache License, Version 2.0 (the "License");
//you may not use this file except in compliance with the License.
//You may obtain a copy of the License at 
//http://www.apache.org/licenses/LICENSE-2.0
//Unless required by applicable law or agreed to in writing, software
//distributed under the License is distributed on an "AS IS" BASIS,
//WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//See the License for the specific language governing permissions and
//limitations under the License.
//========================================================================

package io.protostuff;

/**
 * An input that is stateful and keeps track of the references. This is useful for updating the reference of the last
 * message (polymorphic) deserialized.
 * 
 * @author David Yu
 * @created Jan 19, 2011
 */
public interface GraphInput extends Input
{

    /**
     * Updates the last reference (the tip/end of the index) kept if the {@code lastMessage} was indeed the last
     * message.
     */
    public void updateLast(Object morphedMessage, Object lastMessage);

    /**
     * Returns true if the last message was read as a reference.
     */
    public boolean isCurrentMessageReference();

}
